Initial import from Docker volume

modules/marketing_email/routes.py

@@ -0,0 +1,12 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from trytond.protocols.wrappers import Response
+from trytond.tools import file_open
+from trytond.wsgi import app
+
+
+@app.route('/m/empty.gif')
+def empty(request):
+    fp = file_open('marketing_email/empty.gif', mode='rb')
+    return Response(fp, 200, content_type='image/gif', direct_passthrough=True)